The average human sheds 1.5 million skin flakes in a single hour. The average American at least, spends 90% of their time indoors. Carpet is the most common household flooring choice in the US with 80% of bedrooms and 65% of living rooms being carpeted. As a result dead skin cells contribute greatly to the dirt content in your carpet.
Pet dander is basically skin flakes, oils and hair omitted by animals. Carpet traps this dander allowing it to collect. 15% to 30% of the populace is allergic in some degree to pet dander, many of which don’t even realize it. If you don’t have any pets you wouldn’t expect pet dander to be in your home, however dander can come in on shoes, blow in through doors and windows or be brought in with visitors to be stored in carpet.
Dust mites are a microscopic arachnid that feed on those dead skin cells and animal dander in carpet. Over 100,000 dust mites can be found in around 10 sq feet of carpet. These mites reproduce and die every 3 weeks. While not posing a health risk themselves, dust mites’ fecal pellets and decomposing bodies cause an allergic reaction in 18-30% of the populace. In addition homes that are heavily carpeted have such a high level of dead mites (around 100,000 every three weeks per 10 feet of carpet!) and fecal pellets that 50% of the remaining populace that isn’t allergic to dust mites will also exhibit symptoms of an allergy ranging from common cold like symptoms and skin rashes to difficulty breathing . They may also cause asthma and eczema.
A study done in 2002 found that even non-problematic, moisture free homes with proper cleaning could harbor various fungi species within their padding. In the test a clean bedroom floor with no moisture source present 18 species of active fungus. Increased levels of humidity or moisture from bathrooms, kitchens, plumbing and environmental influence can increase this number. Fungi and molds are another known source of allergies and certain types can release toxic chemicals known as mycotoxins.